Needle (plant)

“ A few small bracts occur at the base of the flower-head, which droops on a small stem. The heads are arranged in little clusters springing from the angles of the branches and leaves.
As the flower-head matures, there may be found within its nodding cup a bunch of fine reddish hairs, like a sable paint brush,—later this opens into a downy seed tassel. The fine stalk gives the plant a distinguished appearance. ”

“ The seeds, under pressure, yield quite a good oil. A yellow dye can be obtained by boiling the roots with alum. An excellent string can also be made from the inner bark of the stems, which has, in fact, been used to make twine and even clothing. The nettle is also valuable as an external stimulant in cases of paralysis.
A plant with so many wonderful properties would not be so common as it is, or so little disturbed, if it were not for its powerful stings.
There are one or two plants which are extremely like the nettle at first sight. ”

“ The tender young shoots of this year's growth are clothed with these close-set needles for a space of a foot or more, averaging ten groups of five needles to the inch, all pointing upward to the very tip, where they press around the buds for next year's growth in a close-inverted cone. They themselves keep the cold winds in a good measure from this young bark and these prized buds. But they do better than that. When the snow begins to fall they catch and hold every flake that touches them, skewering the interstices of the crystals on their needle points. ”

“ In their early state all leaves are continuous with the stem, and it is only in their after growth that articulations are formed. When leaves fall off annually they are called deciduous; when they remain for two or more years they are persistent, and the plant is evergreen. The laminar portion of a leaf is occasionally articulated with the petiole, as in the orange, and a joint at times exists between the vaginal or stipulary portion and the petiole.
The arrangement of the fibro-vascular system in the lamina constitutes the venation or nervation. ”

“ The lobes, exhausted of their farinaceous matter, gradually dry, and fall off of themselves in a few weeks, when the plant has no further need of their assistance.—Certain herbs which grow on the mountains are of a very peculiar nature: their duration being very short, it often happens that the seed has not time to ripen; and, that the species may not be lost, the bud which contains the germ is formed upon the top of the plant, puts forth leaves, falls, and takes root. ”

“ The male flowers are produced in great numbers in drooping catkins at the ends of the branches, shedding the pollen in early spring before the leaves unfold. The female flowers are produced on the same branches, but lower down, and in much smaller numbers. The stigmas are long, and covered with minute hairs that catch the pollen which is shaken out in clouds every time the plant is shaken by the wind, and falls in a shower over the stigmas. ”

“ A microscopical examination of the tissues of the plant shows them to be comparatively simple, this being especially the case with the fibro-vascular system.
The epidermis of the leaf is readily removed, and examination shows it to be made up of oblong cells with large breathing pores in rows. The breathing pores are much larger than any we have yet seen, and are of the type common to most angiosperms. ”

“ The most prominent of these parts are root, stem, leaf, flower, fruit, and seed. Familiar plants differ wonderfully in size and shape,—from fragile mushrooms, delicate waterweeds and pond-scums, to floating leaves, soft grasses, coarse weeds, tall bushes, slender climbers, gigantic trees, and hanging moss.
The Stem Part.—In most plants there is a main central part or shaft on which the other or secondary parts are borne. This main part is the plant axis. Above ground, in most plants, the main plant axis bears the branches, leaves, and flowers; below ground, it bears the roots. ”

“ When alive they are filled with cell sap and protoplasm.
Trace the woody strands through the nodes. Do they ascend vertically? Do they curve toward the rind at certain places? Compare their course with the strands shown in Fig. 70. The woody strands consist chiefly of tough fibrous cells that give rigidity [61] and strength to the plant, and of long tubular interrupted canals that serve to convey sap upward from the root and to convey food downward from the leaves to the stem and the roots. ”

“ By the parent it is provided with a protective wrapping, the seed coat, and beneath this the little embryo swells until it reaches a certain size, when as a ripe seed it severs its connection with the maternal organism. It is important to realise that the seed of a plant is not a sexual cell but a young individual which, except for the coat that it wears, belongs entirely to the next generation. It is with annual plants in some respects as with many butterflies. ”

“ You will also see on this slide several cells in which these tiny spores s are forming, ready to burst out and swim; for this green weed is merely a collection of cells, like the single-celled plants on land. Each cell can [Pg 177] work as a separate plant; it feeds, grows, and can send out its own young spores.
This deep olive-green feathery weed (2, Fig. 63) , of which a piece is magnified under the next microscope (2, Fig. 65) , is very different. It is a higher plant, and works harder for its living, using the darker rays of sunlight which penetrate into shady parts of the pool. ”

“ The young plant has a circle of leaves, about six in number, surrounding a bud which is the growing point of the stem, and in many conifers persists as long as the stem grows (Fig. 75, K, b) . A cross-section of the young stem shows about six separate fibro-vascular bundles arranged in a circle (S, fb.) . The root shows a central fibro-vascular cylinder surrounded by a dark-colored ground tissue. Growing from its surface are numerous root hairs (Fig. 75, M) . ”

“ When the pollen is of full size, or ripe, the little box bursts open, and out the pollen flies. The growth of the plant begins here, with the pollen.
A tiny grain of pollen, falling on the top of the pistil, begins to grow. It puts out little threads like roots. These grow down the stem, or post, of the pistil into the seed case. There they find the seed germs, and when the pollen comes to them, the germs begin to grow. They grow very fast.
It is then that the pretty flowers fade. The work of the blossom is done when the pollen is ripe, and the seed germs begin to grow. ”

“ The plant may at once be recognized by the heart-shaped pods and small, white, four-petaled flowers. The plant begins to flower when very small, but continues to grow until it forms a much-branching plant, half a metre or more in height. On pulling up the plant, a large tap-root (Fig. 93, A, r) is seen, continuous with the main stem above ground. The first root of the seedling plant continues here as the main root of the plant, as was the case with the gymnosperms, but not with the monocotyledons. ”

“ The whole seed of some plants is so small that it can be lifted bodily by the wind, for instance Rhododendrons and many other heaths, one of the hanging pitcher plants of tropical Asia, many orchid seeds, and of hundreds of other plants. Many of these are less than one ten-thousandth of a gram in weight and, with dust and the spores of nearly all cryptogams, may be transported thousands of miles. ”

“ The loose and transparent bag which encloses the seed of the White Water-Lily (Fig. 418) is of this kind. So is the mace of the nutmeg; and also the scarlet pulp around the seeds of the Waxwork (Celastrus) and Strawberry-bush (Euonymus) . The aril is a growth from the extremity of the seed-stalk, or from the placenta when there is no seed-stalk.
Fig. 418. Seed of White Water Lily, enclosed in its aril.
384. A short and thickish appendage at or close to the hilum in certain seeds is called a Caruncle or Strophiole (Fig. 419) .
Fig. 419. Seed of Ricinus or Castor oil plant, with caruncle. ”

“ The plant is found in several varieties affording respectively white, yellowish, reddish, brown or black seeds. The dark seeds may be deprived of a part of their colouring matter by washing, which is sometimes done with a view to obtain a paler oil. ”

“ The young root and leaf now rapidly elongate, and burst through the overlying cells, the former growing downward and becoming fastened in the ground, the latter growing upward through the notch in the front of the prothallium, and increasing rapidly in size (Fig. 67, B) . The leaf is more or less deeply cleft, and traversed by veins which are continuations of the fibro-vascular bundle of the stalk, and themselves fork once or twice. ”

“ A similar production of buds may take place in the flower itself, [Pg 116] either from its centre or from the axil of some of its constituent parts. Prolification of the flower is therefore median or axillary, and the adventitious bud itself may be of a leafy or a floral nature.
Median leafy prolification.—In this malformation the centre of the flower is occupied by a bud or a branch; the growing point or termination of the axis which ordinarily ceases to grow after the formation of the carpels, takes on new growth. ”

“ The staminal tube is more or less deeply cleft into bundles, sometimes almost to the base; pollen smooth, style simple with capitate, lobed stigma. Almost all plants belonging to this group are trees, and in many instances have large barrel-shaped stems, that is, swollen in the centre, and sometimes covered with large warts. The wood is exceptionally light and soft. The flowers are often enormously large, and have beautiful petals; in some they unfold before the leaves. ”

“ The flowering plants have several distinct and visible organs for the formation and fertilization of their seed, to each of which is assigned a special and necessary office. In the flowerless section, on the contrary, there are none of these visibly separate agencies in reproduction, and what are usually termed the seeds do not show any parts representative of the developed product. In the true seeds, which belong to flowering plants alone, are contained the rudiments of a stem, leaves, and root, but in the spores of the flowerless plants nothing of the kind is found. ”

“ The roots of air-plants, such as certain orchids, draw their nourishment from the air.
The experiment of marking roots and stem has been already tried, but it should be repeated. Repetition of experiments is always desirable, as it fixes his conclusions in the pupil's mind. The stem grows by a succession of similar parts, phytomera, each part, or phyton, consisting of node, internode, and leaf. Thus it follows that stems must bear leaves. The marked stems of seedlings show greater growth towards the top of the growing phyton. It is only young stems that elongate throughout. ”

“ As they ripen they become nearly black, the cell bursts, and the earth receives them. The Scilla lengthens its flower-stems until they lie on the ground, forming large seed-pods filled with white pearls. When the plants are taken up, if these little seeds are saved the stock will increase much more rapidly. ”

“ Embryo thread-shaped, spirally coiled in the rather fleshy albumen, destitute of cotyledons, sometimes with a few alternate scales (belonging to the plumule) ; germination occurring in the soil.—Leafless annual herbs, with thread-like yellowish or reddish stems, bearing a few minute scales in place of leaves; on rising from the ground becoming entirely parasitic on the bark of herbs and shrubs on which they twine, and to which they adhere by means of suckers developed on the surface in contact. Flowers small, cymose-clustered, mostly white; usually produced late in summer and in autumn. ”

“ Flowers opening in early spring from buds formed the previous autumn, diœcious or monœcious, axillary and solitary, surrounded by the persistent decussate scales of the buds, the male composed of numerous filaments united into a column, [91] each filament surmounted by several more or less united pendant pollen-cells; the female of a single erect ovule, becoming at maturity a seed with a hard bony shell, raised upon or more or less surrounded by the enlarged and fleshy aril-like disk of the flower; embryo axile, in fleshy ruminate or uniform albumen ”

“ Leaves vary surprisingly in size, shape, and arrangement, features which are closely related to the characters of the stems which bear them, the object being the most advantageous display of the chlorophyll in relation to the light-supply. In general they naturally take the form of a broad thin blade, protected as may be necessary against extremes of weather, and guarded against the obvious danger of being dried up by a thin waterproof covering or cuticle outside the epidermal layer of cells. In leaves we find the same beauty of mechanical construction as is seen in stems. ”

“ The pollen-grains are “multicellular,” i.e. there is always in their interior a distinct prothallium, formed by 1–3 cells, and a larger cell which gives rise to the pollen-tube.
Division 5. Angiospermæ. The carpels surround the ovules and form an entirely closed chamber (ovary) , in which the ovules mature and ripen into seeds. The surface of a portion of the apex of the carpel is transformed into the “stigma,” which, by a sticky fluid and also by hair-structures, is capable of retaining the pollen-grains conveyed to it by the wind, or more frequently by insects. ”